1. Field of the Invention
The invention relates to a projector apparatus, and in particular, to a projector apparatus which utilizes wedge-type lens therein.
2. Description of the Prior Art
In recent years, the projection apparatuses used in the corporate market are getting introduced in the household market or personal market. For applications of personal portable products, the volume size of projection apparatus and the efficiency of optical engine are important issues, and more particularly, the specific angle of incidence required by the reflection-type image generator built in the projector apparatus needs to be considered especially to tradeoff between the volume size and the optical engine efficiency.
In general, the projection apparatus includes a light source module, an illumination lens set, a reflection-type image generator, a prism set, and an image projection lens set, wherein the reflection-type image generator is usually composed of micromirror units. Each of the micromirror units, flips with respect to a diagonal axis thereof and reflects light into the subsequent image projection lens set (i.e. On) or reflects away from the subsequent image projection lens set (i.e. Off) according to a controlling signal. And arrangement of micromirror unit within the reflection-type image generator is categorized into a rectangular-type arrangement (i.e. the diagonal axis tilted 45 degrees relative to a horizontal reference line) and a diamond-type arrangement (i.e. the diagonal axis tilted 90 degrees relative to a horizontal reference line). Therefore, a corresponding angle of incidence is required for different arrangement; otherwise, the reflection-type image generator can not provide the correct and desired image generation function. While meeting with the required angle of incidence, the corresponding location of the prism set thus designed can not satisfies the expected size of volume and, at the same time, the expected efficiency of optical engine.
As disclosed in FIG. 6, as the arrangement of micromirror unit is in rectangular configuration, the required incident direction of the primary light will be from the top-left as shown. Therefore, the optical elements utilized before the prism set need to be disposed on the top-left of the reflection-type image generator. Therefore, a minimum difference value in X direction and in Y direction between them is respectively required.
As disclosed in FIG. 7, as the arrangement of micromirror unit is diamond configuration, the required incident direction of the primary light will be from the left as shown. Therefore, the optical elements utilized before the prism set need to be disposed on the left of the reflection-type image generator. Therefore, a minimum difference in Y direction between them is required.
Accordingly, it is desired to provide a novel design in this field which could reduce the size of volume of projection apparatus and to enhance the efficiency of optical engine as well.